U.S. Pat. No. 4,602,689 describes a hand-held power tool having a pneumatic striking mechanism. A freely moving piston that is excited by a driven exciter piston to execute a periodical movement is arranged in a guide cylinder. The guide cylinder is sheathed with a thermally insulating plastic layer in order to reduce heat losses from an air cushion situated between the exciter piston and the freely moving piston. Moreover, the freely moving piston has a jacket made of plastic in order to improve the thermal insulation. The core of the freely moving piston is made of metal so that it can withstand the mechanical loads. The guide cylinder is made of metal for the same reason.